Fusible link



Dec. 12, 1950 A. c. ROWLEY 2,534,065

FUSIBLE LINK Original Filed April 19, 1946 Jim/81%;":

Patented Dec. 12, 1950 FUSIBLE LINK Arthur C. Rowley, Drexel Hill, Pa., assignor to Globe Automatic Sprinkler Company, Philadelphia, Pa., a corporation of Pennsylvania Original application April 19, 1946, Serial No.

1948. Serial No. 31,770

Claims. (01. 169-42) This invention relates to fusible links for sprinkler heads of automatic sprinkler systems (being a division of application Serial No. 663,532, filed April 19, 1946, on which Patent N0. 2,502,754 issued April 4, 1950) and a principal object of the invention is to provide a generally improved link of that class.

Another object of the invention is to provide a thermo-responsive link of stated class composed primarily of wire or similar relatively inexpensive material.

The invention resides -further in certain structural details hereinafter described and illustrated in the attached drawings wherein:

Fig. 1 is a front elevational view of a sprinkler head made in accordance with the invention;

Fig. 2 is a side elevational view of the sprinkler head;

Fig. 3 is a top plan view of the head;

Fig. 4 is an enlarged sectional view on the line 4-4, Fig. 1;

Fig. 5 is a view in perspective of one of the elements of the yoke constituting a structural member of the device;

Fig. 6 is a sectional view on the line 6-45, Fig. l, and

Fig. 7 is an exploded view in perspective of the elements of the thermo-responsive linkage.

With reference to the drawings, the sprinkler therein illustrated as a medium for describing the form and mode of operation of the fusible link of the present invention comprises a tubular fitting l which is threaded at one end to permit attachment of the fitting to one of the ducts of the sprinkler system in accordance with conventional practice. Conventionally also, the opposite end of the fitting I forms a seat for a closure disc 2 which normally seals the tubular passage 3 through the fitting and which, when released as hereinafter described, permits flow of water from the system.

In accordance with the usual practice, the sprinkler head includes a yoke 4 which extends outwardly beyond the discharge end of the fitting l and supports at its outer end a spreader 5, which may be of any desired form, said spreader being supported in line with the passage 3 so that water discharging from the latter may impinge upon the spreader and be distributed by the latter over the area controlled by the individual head. A thermo-responsive linkage, designated generally by the reference numeral 6, is provided which, in effect, forms a strut between the outer end of yoke 4 and the closure disc 2 to normally hold the said disc to its seat, closing the passage Divided and this application June 8,

through the fitting l as previously set forth. The structural form of the yoke and the structural and functional nature of the thermo-responsive strut device, except as it pertains to the fusible link element hereinafter described which forms an operative part of said structure, constitutes no part of the present invention and will therefore be described in general terms only.

The linkage 6 consists of a pair of elements I and 8 which are shown in perspective in Fig. '7. In assembly the one end 9 of the element 1, which performs the function of a strut, seats with a recess II in the outer surface of the closure disc 2. The opposite edge l2 of the link 9 forms a fulcrum for the off-set end I? of the element 8, as best shown in Fig. 2, this latter element performing the function of a lever as hereinafter set forth. The one leg of the lever 8 extends more or less parallel to the strut element 1 to one side of the latter, and is normally anchored to the strut element by means of a thermo-sensitive or fusible link M which is shown in perspective in Fig. 7. The other end l3 of the lever 8 bears against a sphere l5 which in assembly seats against the inner side of a yoke at the point immediately below the spreader 5, and the arrangement is such that in assembly the lever element 8 and link M are under tension, while the strut element 1 is under longitudinal compression so as to hold the closure disc 2 securely on its seat against fluid pressure within the base fitting I.

As best shown in Fig. 4, the link member 23 consists of cylinder I6 which is made of windings I! of relatively light wire, and the space in the interior of this cylinder is filled normally with a mass of solder or other heat-sensitive material I8. Embedded in the ends of this thermo-sensitive composition at the respective opposite ends of the cylinder I6 is a pair of spherical elements l9l9, the sides of which project beyond the ends of the cylinder l6, but which are retained in place in the cylinder by the said material IS. A bale, 2|, of wire has its ends 22-22 looped around the ends of the cylinder l6 and this bale in assembly embraces the end of the lever 8, as clearly illustrated. The cylinder I6 is positioned generally at the opposite side of the strut element 1 from the lever [B and is prevented from passing through the said element 1 by engagement with the sides of this element of the projecting sides of the spheres l9-l9. This is clearly shown in Fig. 4.

When the thermo-sensitive material [8 is subjected to a predetermined maximum temperature, it fuses, thereby permitting the spheres [9 to move inwardly. As the spheres move inwardly the melted solder escapes between the convolutions E? of the cylinder iii. The cylinder [6 may then pass between the sides of the link i. This releases the stressed lever 8 and permits the entire linkagestructure to collapse, thereby also releasing the closure disc 2 and permitting the fluid in the system to discharge through the pas sage 3 and against the distributor 5.

It will be noted that the link member M is so constituted as not to require theservices of an experienced solderer, it being necessary merely to press the solder or fuse material, which may be in rod form, into the cylinder l 5 and to embed the spheres E9 in the ends.

I claim:

1. A heat releasable link for automatic sprinkler heads, said link comprising a tubular housing, a solid body of heat-fusible medium housed in said tube, the walls of the housing' having interstices permitting passage therethrough of the saidmedium in fused state but being impermeable to the medium in the solid state, and terminal elements normally supported by said body in positions projecting from the ends of the housing and being displaceable inwardly of .the housing upon fusion of the medium.-

2. A linkin accordance with claim lwherein the said housing is formed of .convolutions. of wire,

andwherei-n furtherthe fused medium is adapted.

to .escapebetween said convolutionsa 3.- A closure retaining strut for automatic sprinkler heads com-prising inv combination anapertured-memberand a heat-releasable linkin accordance with claim 1, the width of said aperture being greater than the length of the tubular housing of the link but less than the overall length of the link including the terminal elements, whereby the latter when supported by the said fusible'body and engaged respectively with the opposite edgesof the aperture will prevent the link from passing sideways through the aperture, the projecting ends of said elements having outwardly converging sides so that when REFERENCES CITED The followingreferences are" of record in the.

filer ofthis patent:

UNITED STATES PATENTS Number Name Date 1,231,439 Simonds-et a1. June 26," 1917 1,243,690 Blauvelt Oct. 23, 1917' 1,945,450 Rowley' Jan. 30, 1934 

